Location: Just after entering Blackmarsh, walk past the 'Old Sign' and the tree is the second one on the left side (the first tree is on the right side of the path). The second tree is the dialogue point.

He said evil magic killed everyone here. This was just before the rebellion--a great mystery at the time.

What evil magic could have caused this? / (If triggered after completion of The Blackmarsh) Well, it’s not a mystery now. (+2)

Your father told you stories? (-1)

Did he tell you anything else about this place? (+2)

I used to dream of coming to the Blackmarsh and setting things right. Little boy dreams.

You're doing that now, aren't you? (+2)

If the Veil is thin here, there's no repairing it. (-1)

Every little boy has such dreams. / (If triggered after completion of the Blackmarsh, OR if the Warden is female) You wanted to be a hero? That’s cute. (+1)

Now here I am, a Grey Warden and fighting both darkspawn and demons. Interesting.